nemo-icon-container.c: Keep icon-view rename open across scrollbar allocations

[rolanddeboer]

Prepared by an automated coding agent, not a human maintainer.

A Linux Mint user encountered this bug and asked a Cursor cloud coding agent to investigate and fix it. This pull request was written by that bot. The base model was Grok 4.7. Please review it as an automated contribution.

Fixes #3155
Fixes #3755

Problem

In icon view, F2 rename commits after every keystroke when the window is at the size where a scrollbar is just about to appear or disappear. That includes a maximized window on some monitors. Making the window a few pixels shorter or taller, so it is clearly away from that threshold, makes rename work normally.

Root cause

size_allocate() in nemo-icon-container.c relayouts when the allocation width or height changes. Relayout calls icon_set_position(), which commits an in-progress rename (end_renaming_mode(TRUE)) if the icon moves.

Near the scrollbar threshold, GtkScrolledWindow allocates the view twice (narrower with the bar, then wider without it, or the reverse). Commit 39392d0 (issue #1948) skipped only the first of those allocations (renaming_allocation_count == 1). That covers entering rename mode. Typing changes the editable label's requisition and repeats the allocation pair. The later allocation still relayouts, the grid width changes with the canvas width, the icon moves, and the rename is committed. Every key acts like Enter.

Overlay scrollbars do not change the allocation, which is why this shows up with classic scrollbars.

Fix

While a rename is in progress, skip icon relayout for the whole session, not only the first allocation. If a relayout was needed (scrollbar toggle or a real resize), run it once renaming ends.

Enter, Escape, selection changes, and clicks still commit or cancel as before. The container focus-out handler was left as-is: during rename, keyboard focus is on the editable label, and the commit path for this bug is icon_set_position() during relayout.

How to reproduce

1. Open a folder in icon view.
2. Resize the window until a scrollbar has just appeared (or the window is maximized and happens to sit on that boundary). A few pixels either way should make the bar appear or vanish.
3. Select a file and press F2.
4. Type more than one character.

Before this change, each character commits the name. After it, the edit stays open until Enter, Escape, or an explicit click or selection change.

[mtwebster]

Cleaner fix: b554532